Direct Immobilization of Protein G Variants with Various Numbers of Cysteine Residues on a Gold Surface

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• 作者：Jeong Min Lee ; Hyun Kyu Park ; Yongwon Jung ; Jin Kyeong Kim ; Sun Ok Jung ; Bong Hyun Chung
• 刊名：Analytical Chemistry
• 出版年：2007
• 出版时间：April 1, 2007
• 年：2007
• 卷：79
• 期：7
• 页码：2680 - 2687
• 全文大小：621K
• 年卷期：v.79,no.7(April 1, 2007)
• ISSN：1520-6882

文摘

Protein G is an antibody binding protein, which specifically targets the Fc region of an antibody. It therefore hasbeen widely used to immobilize different types of antibodies in numerous immunoassays. Here, we have engineered Streptococcus protein G to contain various numbers of cysteine residues at the N-terminus and thereforeto form well-oriented protein G films on bare gold. SPRand SPR imaging analyses indicated that a gold surfacetreated with cysteine-tagged protein G possesses a superior antibody binding ability compared to one treated withtag-free protein G. AFM images indicated a higher surfacecoverage by antibody binding on the cysteine-taggedprotein G surface than the intact protein G surface. Theproper orientation of cysteine-tagged protein G on a goldsurface also afforded better orientation of immobilizedantibodies, resulting in enhanced antigen detection.Moreover, the protein G surfaces maintained their highantibody binding ability during multiple rounds of antibody interaction tests. The cysteine-tagged protein Gconstructed in this study can be a valuable link fororiented antibody immobilization in a variety of immunosensors.